Arrangement for counterbalancing the forces in crankshaft driven machines



BRUDERER ARRANGEMENT FOR COUNTERBALANCING THE FORCES IN CRANKSHAFTDRIVEN MACHINES Filed Dec.

United States Patent 3,422,688 ARRANGEMENT FOR COUNTERBALANCING THEFORCES IN CRANKSHAFT DRIVEN MACHINES Egon Bruderer, Neukirch,Switzerland, assignor to Bruderer AG, Arbon, Thurgau, Switzerland FiledDec. 2, 1966, Ser. No. 598,641 Claims priority,applicatio6n6gzvitzerland, Dec. 2, 1965,

US. CI. 74-44 Claims Int. Cl. F16h 21 /22 ABSTRACT OF THE DISCLOSURE Inorder to have quiet operation and to avoid heavy and strong supportingsurfaces, it is necessary with crankshaft driven machines, such as crankand punch presses or embossing machines, to counterbalance the heavyreciprocating parts.

An object of the invention is to provide arrangements for effecting arelatively simple, yet effective, counterbalancing of the reciprocatingparts in a crankshaft driven machine.

In accordance with the invention there is provided an arrangement of theabove character which comprises a member mounted for reciprocation; acrankshaft, a connecting rod pivotally connected to said crankshaft andsaid member for reciprocating the latter when the crank shaft isrotated, two spaced-apart counterweights, one located on each side ofsaid member; an individual pivotally mounted lever pivotally connectedon one side of the pivot point thereof to each of said counterweights;an individual rod pivotally connected to said member and to a respectivesaid lever on the other side of the pivot point thereof, wherebyreciprocation of said member causes a reciprocation in the oppositesense of said counterweights; and means connected to said counterweightsfor preventing uncontrolled swinging of said counterweights duringreciprocation thereof.

The above and further objects of the invention will be apparent from thefollowing detailed description of three embodiments of the invention,with reference to the accompanying drawing, wherein:

FIGURE 1 is a view in cross section of one embodiment of the invention;

FIGURE 2 is a view similar to that of FIGURE 1 of a second embodiment ofthe invention; and

FIGURE 3 is a view similar to that of FIGURE 1 of a third embodiment ofthe invention.

With reference to the embodiment of FIGURE 1, the crankshaft 1 isconnected by a pin to the connecting rod 2, which is pivotally connectedto a reciprocating member, such as a cross head or piston 3, whichreciprocally slides in the machine housing 4. Two rods 5 are pivotallyconnected to the piston 3. Each rod is pivotally connected to one end ofa lever 6 with equal arms and by the lever 6 to one end of a respectivecounter weight 7 which is pivotally connected to the other end of thecorresponding lever 6. The two counter-weights are located on oppositesides of the piston 3 and their broad surfaces extend trans- 3,422,688Patented Jan. 21, 1969 versely to the stroke direction of the piston.The other end of each counter-weight is connected to the housing 4 byrespective pivotally mounted rods 8. When the crankshaft 1 rotates, thetwo counter-weights 7 moves reciprocally in the direction of the pistonstroke but in a sense always opposed to the latter, whereby the forcesarising from the reciprocating ports are counterbalanced.

In the embodiment of FIGURE 2 the counter-weights 7 are pivotallyconnected together by a pivot 12, and thereby are prevented fromswinging loosely from their pivotal connection to the levers 6.

In the embodiment of FIGURE 3 the rods 8 are replaced by the pivotallymounted rods 9, which are pivotally connected to the shorter arm ofrespective pivotally mounted levers 10, the longer arms of which arepivotally connected to respective rods 11 which are pivotally connectedto the crankshaft 1. The counter-weights 7 move in the direction of thepiston stroke but in the opposed sense. They also have a component ofmovement that is transverse to the piston stroke, whereby the forcesarising from rotation of the crankshaft 1 are also counterbalanced.

The arrangement of the counter-weights and their drive from thecrankshaft is completely isolated from the main crank assembly of themachine (not shown), in the embodiments described. The counter-weightsin no way adversely influence the correct operation of the machine.

With machines having an adjustable-stroke main crank assembly, thestroke of the counter-weights is automatically changed an equal amount.

The invention is not to be construed as limited to the particular formsdisclosed herein, since these are to be regarded as illustrative ratherthan restrictive.

I claim:

1. Arrangement for counterbalancing the reciprocating parts of acrankshaft driven machine, including a member mounted for reciprocation;a crankshaft, a connecting rod pivotally connected to said crankshaftand said member for reciprocating the latter when the crankshaft isrotated, two spaced-apart counter-weights, one located on each side ofsaid member; an individual pivotally mounted lever pivotally connectedon one side of the pivot point thereof to each of said counter-weights;an individual rod pivotally connected to said member and to a respectivesaid lever on the other side of the pivot point thereof, wherebyreciprocation of said member causes a reciprocation in the oppositesense of said counter-weights; and means connected to saidcounter-weights for preventing uncontrolled swinging of saidcounter-weights during reciprocation thereof.

2. The arrangement as defined in claim 1, wherein each said lever hasequal arms, and said means for preventing uncontrolled swinging of thecounter-weights comprise an individual rod pivotally connected to arespective counterweight and to a fixed point.

3. The arrangement as defined in claim 1, wherein said means forpreventing uncontrolled swinging of the counter-weights comprises apivot connecting together said two counter-weights.

4. The arrangement as defined in claim 1, wherein said means forpreventing uncontrolled swinging of the counter-weights comprises anindividual pivotally mounted twoarm lever pivotally connected on oneside of the pivot point thereof to each said counter-weight, anindividual rod pivotally connected at one end to a respective saidtwo-arm lever and at the other end to said crankshaft at a pointeccentric from the center thereof, whereby each counter-weight is causedto have a component of movement that is transverse of the movement ofsaid member, for counterbalancing the forces arising from the rotationof said crankshaft.

5. The arrangement as defined in claim 4, including an 3 individual rodpivotally connected to a respective said counter-Weight and to thecorresponding said two-arm lever on said one side of the pivot pointthereof.

References Cited UNITED STATES PATENTS FRED C. MA'ITERN, JR., PrimaryExaminer. 5 WESLEY S. RATLIFF, Assistant Examiner.

US. Cl. X.R.

